1. Field of the Invention
The invention relates to systems for receiving digital communication signals which are modulated onto a carrier in the form of binary frequency modulation and radiated through a propagation medium which is subject to reflection and particular for reception by mobile stations, long distance traffic connections and scattered beam connections.
2. Description of the Prior Art
In digital communication transmission systems under heavily disturbed propagation conditions such as multi-path propagation the range is approximately inversely proportional to the level of the bit rate which is to be transmitted. The critical situation which determines the range consists of total information erasure, wherein due to the differing transit times caused by the path differences between the reflected carrier waves, the modulation signals arrive at the receiver with opposing phase and cancel out each other. Over a wide range before this critical situation partial information losses occur due to the transit time and due to amplitude distortions which cause very high error rates during transmission.